Pulsed-field gel electrophoresis was proven to be an efficient means of differentiating 25 strains of Bifidobacterium obtained from culture collections. XbaI, SpeI, DraI restriction enzyme profiles indicated genomic heterogeneity among strains. When seven human isolates of bifidobacteria were compared using the same methods, two individual banding patterns were obtained. However, despite its discriminatory potential, pulsed-field gel electrophoresis was shown to be of no value in taxonomic identification. Genomic sizes estimated for eight Bifidobacterium strains ranged from 1.5 Mb to 2.1 Mb.